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Quiz: Prevention Science

Test your understanding of the prevention spectrum, evidence hierarchies, implementation frameworks, and harm reduction with these review questions.

1. The Institute of Medicine (IOM) spectrum of prevention classifies interventions into three tiers. "Selective prevention" targets:

  1. The entire population regardless of risk level
  2. Individuals or subgroups with elevated risk compared to average
  3. Individuals already showing early signs or symptoms of a condition
  4. Individuals with established diagnoses receiving secondary treatment
Show Answer

The correct answer is B. The IOM framework divides prevention into universal (entire population), selective (subgroups at above-average risk based on biological, psychological, social, or environmental risk factors), and indicated (high-risk individuals showing early markers of a condition). This tripartite classification helps match intervention intensity to risk level — universal strategies are lower-cost per person and reach everyone; selective and indicated strategies justify higher-intensity, higher-cost interventions for those most likely to benefit.

Concept Tested: IOM Prevention Spectrum

2. The Haddon Matrix analyzes injury prevention by examining:

  1. The epidemiological triad (host, agent, environment) at pre-event, event, and post-event phases
  2. The cost-effectiveness of injury interventions compared to clinical treatment
  3. Individual risk-taking behavior as the primary modifiable determinant of injury
  4. The legal liability of manufacturers, operators, and individuals in injury events
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The correct answer is A. The Haddon Matrix is a structured framework for systematically identifying injury prevention opportunities. It crosses the three phases of injury events (pre-event, event, post-event) with three factors (host, agent/vehicle, environment), generating nine cells — each representing a potential point of intervention. The matrix reveals that injury prevention need not target only the host (victim/driver) behavior; many high-leverage interventions address the agent (vehicle crashworthiness) or environment (road design).

Concept Tested: Haddon Matrix

3. Which of the following represents the highest level of evidence in a hierarchy for evaluating public health interventions?

  1. A well-designed case-control study with large sample size
  2. Expert opinion based on clinical experience
  3. A systematic review or meta-analysis of randomized controlled trials
  4. A large prospective cohort study with long follow-up
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The correct answer is C. Evidence hierarchies for intervention effectiveness place systematic reviews and meta-analyses of RCTs at the apex, because they synthesize all available experimental evidence and provide more robust estimates than any single study. RCTs follow, then quasi-experimental designs, then observational studies (cohort, case-control), and then expert opinion at the base. Applied to public health interventions, this hierarchy informs resources like the Community Guide and USPSTF recommendations.

Concept Tested: Evidence Hierarchy for Interventions

4. Herd immunity as a public health goal is achieved through vaccination coverage at the herd immunity threshold (HIT). For measles with R₀ ≈ 15, the approximate HIT is:

  1. 50%
  2. 67%
  3. 80%
  4. 93%
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The correct answer is D. HIT = 1 − 1/R₀ = 1 − 1/15 ≈ 0.933 = 93%. Measles is among the most transmissible vaccine-preventable diseases, requiring very high coverage to interrupt transmission. This is why outbreaks occur even in highly vaccinated communities when coverage drops below 95%: pockets of susceptible individuals can sustain local transmission. The high threshold makes measles particularly vulnerable to vaccine hesitancy in any subpopulation.

Concept Tested: Herd Immunity Threshold for Measles

5. The EPIS framework for implementation science describes four phases: Exploration, Preparation, Implementation, and Sustainment. The "Exploration" phase involves:

  1. Adapting an evidence-based intervention for the local context and workforce
  2. Assessing fit between a potential innovation and the organization's needs and capacity
  3. Full-scale delivery of the intervention with fidelity monitoring
  4. Embedding the intervention into routine practice and funding structures
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The correct answer is B. The EPIS (Exploration-Preparation-Implementation-Sustainment) framework describes the outer system (policy and funding environment) and inner system (organizational context) in which implementation occurs. The Exploration phase involves assessing organizational readiness, identifying potential innovations, and determining whether a given evidence-based practice fits the local context and population needs — before investing in adaptation and training. Skipping thorough exploration is a common reason implementations fail.

Concept Tested: EPIS Framework — Exploration Phase

6. Harm reduction approaches to substance use are grounded in which principle?

  1. Complete abstinence is the only acceptable goal of substance use treatment
  2. Reducing the harms associated with substance use is a legitimate public health goal even without requiring cessation
  3. Legal penalties for drug possession are the most effective deterrent to harmful substance use
  4. Substance use disorders are a matter of individual moral failure requiring personal accountability
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The correct answer is B. Harm reduction accepts that some individuals will continue to use substances regardless of abstinence-based messages, and aims to minimize the associated harms without requiring cessation. Examples include needle exchange programs (reducing HIV and hepatitis transmission), naloxone distribution (reversing opioid overdose), supervised consumption sites, and fentanyl test strips. Evidence supports these approaches as cost-effective public health interventions that save lives and provide pathways to treatment.

Concept Tested: Harm Reduction Principles

7. The Community Guide (The Guide to Community Preventive Services) is best described as:

  1. A federal regulatory database listing approved community health interventions
  2. A systematically reviewed repository of evidence-based recommendations on community health interventions
  3. A directory of community health centers funded by HRSA across the United States
  4. A grant program funding local public health innovation projects
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The correct answer is B. The Community Guide, produced by the Community Preventive Services Task Force, is a publicly accessible resource of evidence-based recommendations across a wide range of public health topics — obesity, tobacco, vaccines, mental health, violence prevention, and more. Recommendations are based on systematic reviews of the peer-reviewed literature and categorized as "recommended," "recommended against," or "insufficient evidence." It is a primary resource for public health practitioners making evidence-based program decisions.

Concept Tested: Community Guide / Community Preventive Services

8. "De-implementation" in prevention science refers to:

  1. The systematic removal of ineffective or harmful practices from routine use
  2. The scaling down of a prevention program when funding ends
  3. The evaluation of an intervention after its initial implementation period
  4. The adaptation of an evidence-based program for a new population
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The correct answer is A. De-implementation is the deliberate and systematic process of reducing or eliminating clinical or public health practices that are shown to be ineffective, harmful, or lower value than alternatives. It is distinct from program discontinuation due to funding loss. De-implementation science addresses the barriers (clinical inertia, financial incentives, patient expectations) that maintain low-value practices in routine use even after evidence of ineffectiveness — a critical challenge given how many established practices lack rigorous evidence support.

Concept Tested: De-implementation Science

9. Geoffrey Rose's prevention paradox states that:

  1. Preventive interventions cause more harm than benefit when applied to low-risk populations
  2. A large proportion of cases in a population often come from individuals at moderate, not high, risk — so population-wide strategies may prevent more disease than high-risk targeting alone
  3. Prevention programs funded by governments are systematically more effective than those funded by industry
  4. The effectiveness of a preventive intervention paradoxically decreases as coverage increases
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The correct answer is B. Rose's prevention paradox observes that because moderate-risk individuals vastly outnumber high-risk individuals in a population, a large fraction of all cases may come from the large group at moderate risk — even though individual risk is low. A population-wide strategy that shifts the entire risk distribution (e.g., reducing average sodium intake) may prevent more cases than targeting only the small high-risk group with intensive intervention, even though each individual in the population benefits little. Both strategies are complementary.

Concept Tested: Rose's Prevention Paradox

10. Fidelity monitoring during program implementation refers to:

  1. Financial auditing to ensure grant funds are spent according to program budgets
  2. Assessing the degree to which a program is delivered as designed, including content, dose, and quality
  3. Monitoring participant retention and dropout rates over the program period
  4. Evaluating whether the program achieved its intended health outcomes
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The correct answer is B. Implementation fidelity refers to how faithfully an evidence-based intervention is delivered as designed. Fidelity monitoring typically assesses: adherence (were all prescribed components delivered?), dosage (were sessions held at the recommended frequency and duration?), quality (how skillfully were components delivered?), and participant responsiveness. Low fidelity is a common reason program evaluations show weaker effects than the original efficacy trial — the "voltage drop" from controlled trial to real-world delivery.

Concept Tested: Implementation Fidelity